AbstractBackgroundLung involvement in children with Niemann–Pick disease has rarely been studied systematically.ObjectiveTo assess the involvement of the lung and the value of bronchoalveolar lavage in children with Niemann–Pick diseases.DesignRetrospective analysis of patient records.PatientsThirteen patients, with type A (n = 1), type B (n = 10), and type C (n = 2) Niemann–Pick disease, aged 2 months to 9 years at diagnosis, were included in the study.InterventionsLung involvement was assessed by clinical evaluation, chest radiograph, lung computed tomography (CT) scan, pulmonary function tests, and bronchoalveolar lavage fluid analysis.ResultsRespiratory symptoms were present at diagnosis in 10 patients and developed during follow up in the three other patients. All patients showed signs of interstitial lung disease on chest X‐ray and lung CT scan. Bronchoalveolar lavage fluid analysis (n = 7) revealed a marked accumulation of foamy macrophages (Niemann–Pick cells) in all patients. At follow up, one patient died of respiratory failure, five patients required long term oxygen therapy and seven other patients presented a chronic obstructive pulmonary disease (n = 6) or chronic cough (n = 1).ConclusionLung disease was observed in all the patients included in the present study. Bronchoalveolar lavage may be useful in Niemann–Pick diseases by showing the presence of characteristic Niemann–Pick cells. Pediatr Pulmonol. 2007;42:1207–1214. © 2007 Wiley‐Liss, Inc.